A disruption in telecommunications service is typically caused by an inoperable communications path (link) or switching office. A disruption of such a service could be very costly to business users who rely on telecommunications services in the operation of their respective businesses. For example, a business could lose revenue as a result of a failure to receive so-called "telemarketing sales" when a disruption in telecommunications services occurs. Moreover, the amount of lost revenue would be directly proportional to the duration of the disruption.
Most telecommunications networks typically deal with a service disruption by establishing an alternate route around the inoperable link or switching office. One goal in doing so is to select the most efficient alternate route, one having the least number of nodes and links. The task of identifying such an alternate route in a small network comprising a small number of nodes (switching offices) and links is typically a simple matter. The reason for this is that the number of alternate routes that may be used for a particular failed link is usually small. However, the task of identifying the most efficient alternate routes in a large communications network composed of a large number of nodes and links is not an easy task. The reason for this is that in a large network the number of alternate routes that may be used for the rerouting of traffic is also large, thereby making the selection of the most efficient alternate route difficult to identify.
Accordingly, there is a need for an arrangement which quickly establishes alternate routes circumventing an inoperable link or switching office, such that a service disruption is virtually transparent to the telecommunications user (subscriber).